A study published in the Royal Society Open Science found that domestic cats have smaller cranial volume, aka brain size, than their ancestors.
The researchers state that reduced brain size is a key characteristic of domesticated mammal species and is often cited as a key component of “domestication syndrome.” Sheep, dogs, and rabbits show the same results.
Note: Domestication syndrome was first proposed by Darwin, who noted heritable traits in domesticated animals that were not seen in wild ancestors. A 2014 paper in Genetics says domestication syndrome “has remained a conundrum for more than 140 years.”
In this study, the researchers repeated old studies that compared the brain sizes of wild cats, domestic cats, and hybrids. The data indicate that domestic cats do have smaller cranial volumes relative to both European wildcats and the wild ancestors of domestic cats, the African wildcats, verifying older studies.
They also found that hybrids of domestic cats and European wildcats have cranial volumes that cluster between the two species. These results are relevant to causes of domestication syndrome.
Lesch, R., et al. “Cranial volume and palate length of cats, Felis spp., under domestication, hybridization and in wild populations.” Jan. 26, 2022. The Royal Society.